Low pressure on Breville Dual Boiler shots

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IMAWriter
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#1: Post by IMAWriter »

In the last maybe 3 weeks, I've noticed my shot pressures (normally steady at 9 bar, are pulling at 8 and below...5 seconds PI at 62...same basically as always.
I've recalibrated my Niche...which ended up near exactly to the dot as before. Here's what's odd...when I do a end of session 15 second blind filter back flush, it reads perfectly, as always...10.5 on the nose, and holds there the entire 15 seconds.

I opened some 2 day old Yemen..still blowing off gas, ground 18 grams into the stock filter, ground to the setting where things were previously fine.
Pulled the shot...same few spins with a leveler, tamp...as always....the shot looked good, pulled fast at 7.5 bars and slightly falling.

So...is it a one year old basket, a one year old group screen..a combo of both? I saw no leaking in the machine. I'll test with an IMS Barista Pro nano basket tonight. If that doesn't help, I'll switch out the group screen with my IMS. I can't think my Nche burrs would have suddenly changed...they've had probably 25-30 kilos through them..if not more.
TIA!

The group gasket looks perfect, as does the black group screen holder.
Rob
LMWDP #187
www.robertjason.com

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checkwhatsleft

#2: Post by checkwhatsleft »

You said that 2 days old bean was pulling good shots and I guess that's the problem is, previous beans were staled that caused fail shots not the shower screen or basket etc.

IMAWriter (original poster)
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#3: Post by IMAWriter (original poster) »

My bad. The shot looked fine, but also poured fast. I have to assume it's the Niche. Strange though, as a recalibrate didn't help. I tightened the grind and will see what's what in a while.
Rob
LMWDP #187
www.robertjason.com

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sweaner
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#4: Post by sweaner »

What does the pressure do if you use a blind basket?
Scott
LMWDP #248

JRising

#5: Post by JRising » replying to sweaner »

10.5 bar, machine's working perfectly. There's a difference in the current batch of coffee, or prep. Maybe humidity, maybe the roast. Adjust the grinder for it and see if you can get a good espresso.

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cafeIKE
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#6: Post by cafeIKE »

Heat & Humidity changed much?

2 bar is a lot for those variables.

I have a pal who had a Breville DB that started leaking water internally. IIRC, similar symptom. The 10+ bar backflush would seal the joint. Shot pressure leaked.

PM if you check, find an internal leak and need silicone gaskets.

IMAWriter (original poster)
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#7: Post by IMAWriter (original poster) » replying to cafeIKE »

Ike, you and john made good points. It's been raining, 93 degrees, so that could be a bit of it. I believe my Niche must have "self-adjusted!" haha.
I moved it 2 notches finer, problem solved.

As to the leak/back flush seal, etc...Shining a flashlight in, I see no leaking at the pump, nor on the bottom of the machine. Also, I've not seen an unusual drop in reservoir level. That said, I think I'll get a brighter, larger light for another look inside. For grins, I might order a couple of Cafelat gaskets.
Thanks to all!!!
Rob
LMWDP #187
www.robertjason.com

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cafeIKE
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#8: Post by cafeIKE »

I should have said 'silicone o-rings'
There are two sizes and plenty of them that keeps the water inside.

I have a Niche from the Indiegogo release. It has always drifted. I got updated springs, to no avail.


from Piano Tuning Mutes 2-9/16" x 1/4" - Set of 4 Rubber Mutes
Trim them down so they fit under the lid. Grind does not move at all.

As any old time piano tuner will tell you, it's important to buy these or identical mutes as the cheap ones disintegrate.

IMAWriter (original poster)
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#9: Post by IMAWriter (original poster) »

cafeIKE wrote:I should have said 'silicone o-rings'
There are two sizes and plenty of them that keeps the water inside.

I have a Niche from the GoFundMe release. It has always drifted. I got updated springs, to no avail.

image
from Piano Tuning Mutes 2-9/16" x 1/4" - Set of 4 Rubber Mutes
Trim them down so they fit under the lid. Grind does not move at all.

As any old time piano tuner will tell you, it's important to buy these or identical mutes as the cheap ones disintegrate.
Yeppers. I have read nearly ALL the BDB threads...Peter Russell is my hero...Lancelot, etc all such giving folks. I have the #7 seals on the ready.need to get 9s(?)...but so far no leaks, and the wandering Niche is behaving as before.

BTW, thanks to Dan K for amending my thread title.
Rob
LMWDP #187
www.robertjason.com

clc12rock

#10: Post by clc12rock »

Funny, I was about to start a similar thread and this was at the top of the first page. My pressure has been dropping the past few weeks and got down to like 3 bar the past couple days. Finally opened up the machine and replaced 5 O Rings: 3 on the steam boiler and 2 on the brew boiler. Just pulled a shot and replacing the o rings got it back up to 7ish. Also went through the cleaning cycle with the blind basket and it got up to 8 bars.

What are these seals you are buying?

Also, would this fit my machine? https://caffewerks.com/collections/gask ... ket-bundle

I think mine is the 920 or something, so I assume that's the right one, but just wanted to confirm before I pulled the trigger.